两种经过不同热处理制成的镍钛旋转器械的抗断裂性能
resistance to fracture of two nickel-titanium rotary instruments made with different thermal treatments.
作者信息
Miccoli Gabriele, Gaimari Gianfranco, Seracchiani Marco, Morese Antonio, Khrenova Tatyana, Di Nardo Dario
机构信息
Department of Oral and Maxillo-Facial Sciences, "Sapienza" University of Rome, Rome, Italy.
出版信息
Ann Stomatol (Roma). 2017 Nov 8;8(2):53-58. doi: 10.11138/ads/2017.8.2.059. eCollection 2017 Apr-Jun.
AIM
Aim of the study was to evaluate effectiveness of different heat treatments in improving Ni-Ti endodontic rotary instruments' resistance to fracture.
METHODS
24 new NiTi instruments similar in length and shape: 12 M3 instruments, tip size 25 and .06 taper (United Dental, Shanghai, China), and 12 M3 Pro Gold instruments tip size 25 and .06 taper (United Dental, Shanghai, China), were tested in a 60° curved artificial root canal. Each group received a different heat treatment. Cycles to fracture were calculated for each instrument. Differences among groups were evaluated with an analysis of variance test (significance level was set at P<0.05.).
RESULTS
Statistical analysis found significant differences (p<0.0213) between groups. The M3 Pro Gold instruments were significantly more resistant to fatigue (mean values = 1012, SD +/- 77) than M3 instruments (mean values = 748, SD +/- 62). No statistically significant differences were found between fragments' lengths (p>0,05).
CONCLUSIONS
An increased flexibility and the reduction of internal defects produced by heat treatments during or after manufacturing processes, may be responsible for improving resistance to cyclic fatigue and flexural stresses.
目的
本研究旨在评估不同热处理方法对提高镍钛根管旋转器械抗折断性能的有效性。
方法
选用24支长度和形状相似的新型镍钛器械：12支M3器械，尖端尺寸25，锥度0.06（联合牙科，中国上海），以及12支M3 Pro Gold器械，尖端尺寸25，锥度0.06（联合牙科，中国上海），在60°弯曲的人工根管中进行测试。每组接受不同的热处理。计算每支器械的折断循环次数。采用方差分析检验评估组间差异（显著性水平设定为P<0.05）。
结果
统计分析发现组间存在显著差异（p<0.0213）。M3 Pro Gold器械比M3器械对疲劳的抵抗力显著更强（平均值 = 1012，标准差±77），而M3器械的平均值为748，标准差±62。碎片长度之间未发现统计学上的显著差异（p>0.05）。
结论
制造过程中或之后的热处理所带来的柔韧性增加和内部缺陷减少，可能是提高抗循环疲劳和弯曲应力能力的原因。
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